Circuit breaker



D. HAYS CIRCUIT BREAKER Feb. 21, 1939.

Filed Aug. 27, 1936 5 WW o w t o n t $3M Q Patented Feb. 21, 1939 UNITED STATES PATENT OFFICE 2,148,295 CIRCUIT BREAKER David Hays, Fairfield, Conn., assignor to General Electric Company, a corporation of New York are to a large extent satisfactory for the pur-v poses intended. Something is yet to be desired, however, in devices of this type which are ex tremely reliable in their operation, which are inexpensive to construct, and which consist of a minimum number of parts compactly arranged. In carrying out my invention in one .form, I provide a floating switch member having movable pivot means, current-responsivelatch means for normally engaging the switch member, and snapacting toggle means for moving the pivot means so as to operate the switch member between open and closed circuit positions, the switch member pivoting about the latch means. Biasing means are also provided for rotating the switch member about the pivot means to the open circuit position when the switch member is released by the current-responsive latch means on the occurrence of predetermined current conditions.

For a more complete understanding of my invention, reference should now be had to the drawing in which'Fig. 1 is an elevational view, partly in section, of a circuit breaker embodying 36 my invention; Figs. 2 and 3 are similar views illustrating the circuit breaker parts in different operating fisitions; and Fig. 4 is an exploded perspective view of the operating mechanism of the circuit breaker shown in Fig. 1.

Referring now to the drawing, I have shown my invention as applied to a circuit breaker having a base III formed of suitable insulating material on which is mounted a U-shaped frame H which supports the operating mechanism. Supported on the base Ill adjacent the frame ll,

l2, each of which supports at its outer end a contact member It in a position to be engaged by cooperating movable contacts ll which are carried'on the opposite ends of a U-shaped bridging member I, the bridging member l5 forming part of a floating switch member, the construction and operation of which will be fully described hereinafter'. In order to minimize rebound of the contacts when the movable contacts II are oper- I provide a pair of flexible conducting members ated into engagement with the stationary contacts [3, the conductors l2 are formed of resilient material and are maintained slightly under tension when the circuit breaker is in its open circuit position by supporting members .IB, as shown 5 best in Figs. 2 and 3. Although only one supporting member 16 is shown in the drawing, it will be understood of course that a separate supporting member is provided for each of the resilient conductors I2.

As shown best in Fig. 4, the bridging member I5 is carried on a supporting member I! which is secured to a framelike member in any suitable manner, for example, by rivets .l9, and is insulated from the member l8 by suitable insulating plates 20. Adjacent its opposite end, the framelike member I8 is provided with a crossportion 2| which is arranged to be engaged by a latch 22 supported on the yoke portion of a U-shaped bi-metallic thermal element 23 (Fig.

4), each leg of the U-shaped thermal element being secured to a terminal member 24, which terminal member is secured to the base l0.

Intermediate its ends, the floating switch member which is formed by the frame It and the member I1 is provided with a crosswise extending pivot pin 25, the opposite ends of which extend into suitable slots 26 formed in the legs of the U-shaped frame ll.

Arranged between the sides of the member l8 and the legs of the U-shaped frame II, I provide a pair of supporting toggle links 21 which are provided with suitable apertures 28 through which the ends of the'pivot pin extend. Pivotally connected to the respective opposite ends of the links 21,1 provide a pair of bell-crank levers 29, each of which is pivoted on a pin 30 which extends inwardly from one of the legs of the U-shaped frame ll. As shown, the bell-, crank levers 29 are connected together by a pin 3| to form a unitary structure, and it will thus be apparent that the links 21 and 29 form a togglemechanism which supports and guides the pivot pin 25. of the floating switch member for movement along the slots 28.

Pivotally mounted on a pin 32 which is supported on the outermost ends 01' the U-shaped frame H, I provide a substantially U-shaped operating lever 33, the yoke portion of which carries a handle 34 formed of suitable insulating material. As shown *best in Fig. 4, one leg ofthe U-shaped operating 1ever'33 extends beyond the pivot point of the lever and is provided with. an inwardly extending finger 35 which carries a suitable lug 26. As shown in Figs. 1, 2 and 3,

when the operating mechanism of the circuit breaker is assembled, the finger on the operating lever extends inwardly through a slot 3i formed in one leg of the U-shaped frame ii, and an over-center spring 38 is provided, one end of which is connected to the lug 35 and the other end of which engages the pin 3i carried by the bell-crank levers 29. In order to provide for assembly of the operating lever 33 relative to the frame H, the slot 3! may be formed with suficient width to permit the lug 86 to pass therethrough, or a suitable notch 39 (Figs. 1 and 3) may be provided along one side of the slot 3? to permit passage of the lug 36 when the finger 35 is inserted into the slot 3?.

Each of the toggle links 21 is provided, as shown, with an extending finger 40, and a suitable torsion spring 4l, which surrounds the pivot pin 25 between the opposite sides of the framelike member I8, is arranged with one end engaging the framelike member l8 and the other end engag g one of the fingers 40. Thus the switch member which carries the movable contacts M is biased for movement in a counterclockwise direction,'as viewed in the drawing, about the pivot pin 25 and is normally maintained in the positions shown in Figs. 1 and 2 by engagement of the latch member 22 with the cross-member 2!.

It is now believed that a complete understanding of my invention may be had from a description of the operation. It will be understood of course that the circuit breaker may be connected in an external circuit to be controlled by connecting one of the flexible conductors it to an external terminal, and by connecting one of the terminals 24 of the bi-metallic element 23 to a similar external terminal, a suitable conductor, not shown, serving to connect the other flexible conductor 82 to the other terminal 2t. of the thermal element. Thus when the circuit breaker is in its closed position shown in Fig. l, a circuit is completed which extends from one of the conductors I 2 by way of the contacts 53 and it and the bridging member it to the other flexible conductor, by way'of the above-referred to connection, not shown, to one terminal of the thermal element 23, and through the ther= mal element to the other one of the terminals 2%.

In Fig. 1, the circuit breaker is shown in its closed circuit position, in which position thespring 38 biases the crank levers 29 to the position shown, so as tormaintain the pivot pin 25 in the extreme right-hand end of the slot 26, and the latch 22 restrains the switch member against rotation about the pivot pin 25 so that the movable contacts it are held in engagement with the stationary contacts it. In order to open the circuit breaker manually, it is necessary only to move the handle 3 upwardly from the position shown in Fig. 1 toward the position 'shown in Fig. 2. As the handle 3d is moved upwardly, the operating lever 33 rotates in a counterclockwise direction about its pivot 82 and, accordingly, the finger 35 moves down wardly in the slot 3?, so as to carry the spring ate the switch member to the open-circuit position shown in Fig. 2, the pivot pin 25 moving along the slot 26, and the switch member pivoting about its point oi engagement with the latch 22. Reclosure of the circuit breaker may be effected simply by returning the handle 34 to the position shown in Fig. 1, the spring 38 thereupon passing overcenter in .the opposite direction and rotating the bell-cranks 29 so as to move the links 2? and the pivot pin 25 to the position shown in Fig. i.

It will thus be seen that the crank lever 29 and the links it constitute toggle means for moving the pivot pin 25 along the slots 26. Although in the embodiment of my invention shown, the toggle does not move to a completely locked position, it will be apparent that if it is desired that the switch" member be locked in'its closed vcircuit position, the links 29 and 21 may be sition shown in Fig. 3. This fiexure of the bimetallic element withdraws thelatch 22 from engagement withthe cross-member 2! on the floating switch member, and the switch member is immediately rotated in a counterclockwise disection about the pivot 25 by the torsion spring at from the closed circuit position shown in Fig. 1 to the open-circuit position shown in Fig. 3.

In "this open-circuit position, the supporting member ill which forms part of the floating switch member engages a suitable stop pin 42 which extends crosswise between the legs of the U-shaped frame it, and in order to reclose the circuit breaker after an automatic operation to its open-circuit position, it is necessary only to move the handle 36 from the position shown in Fig. 3 to the ofi position shown in Fig. v2, whereupon the overcenter spring 38 will operate the toggle links 29 and 2? so as to move the switch inember to the position shown in Fig. 2. As soon as the thermal element 23 has cooled sufflciently to reengage the latch 22 with the cross-member 25, the circuit breaker may be reclosed by operating the handle 34 from the position shown in Fig. 2 to the position shown in Fig. 1.

While I have shown a particular embodiment of my invention, it will be understood, of course. that I do not wish to be limited thereto, since many modifications may be made and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

l. A circuit breaker comprising a floating .mernber, current=responsive latch means normaliy engaging said switch member. a pair oi links, a movable pivot connection joining said links to form a toggle, a connection between one end of said toggle and said pivot means, spring means for operating said toggle with a snap action to thereby move said pivot meansbetween two positions with a snap action whereby said switch member is pivotally moved about said latch means between open and closed circuit positions, and a second spring means biasing said switch member for rotation about said pivot means to an open-circuit position upon release of said latch means in response to predetermined current conditions.

2. A circuit breaker comprising a floating switch member, movable pivot means for supporting said member intermediate its ends, current-responsive latch means normally engaging one end of said switch member, a pair of links, a movable pivot connection joining said links to form a toggle, a connection between one end of said toggle and said pivot means, spring means for operating said toggle with a snap action to thereby move said pivot means between two positions with a snap action whereby said switch member is pivotally moved about said one end between open and closed circuit positions, and

a second spring means biasing said switch member for rotation about said pivot means to an opencircuit position upon release of said latch means in response to predetermined current conditions.

3. A circuit breaker comprising a floating switch member, movable pivot means for said member, a bi-metallic thermal element having a latching portion abuttingly engaging said switch member remote from said pivot means, a pair of links, a movable pivot connection joining said links to form a toggle, a connection between one end of said toggle and said pivot means, spring means operating said toggle with a snap action for operating said pivot means between two positions whereby said switch member is pivoted about said latching portion of said thermal element between open and closed circuit positions, and a second spring means biasing said switch member for "rotation about said pivot means to an open-circuit position, said thermal element upon the occurrence of predetermined current conditions releasing said switch member for movement about said pivot means.

4. A circuit breaker comprising a floating switch member, a pair of links, a movable pivot connection joiningsaid links to form a toggle, a fixed pivot for one end of said toggle, pivot means connecting the other end of said toggle to said switch member, means biasing said switch member for rotation about said pivot means, current responsive latch means normally engaging said switch member for restraining said member against rotation about said pivot means, and means for operating said toggle to thereby move said pivot means whereby said switch member is pivotally moved about said latch means between open and closed circuit position, said current responsive latch means being arranged to release said switch member for rotation about said pivot means to an open circuit position independently of said toggle upon the occurrence of predetermined current conditions.

5. A circuit breaker comprising a frame, a floating contact lever having a pivot pin intermediate its ends, guide means on said frame for guiding said pivot pin, spring means biasing said switch member for rotation about said pivot pin, thermal means for releasably latching said switch member against rotation about said pivot pin, toggle means including a pair of links pivotally connected together and movable with relation to each other to move said pivot pin along said guidemeans to operate said switch member between open and closed circuit positions independently of said thermal means, and a second spring means for operating said toggle means with a snap action to'snap said switch member from each position to the other, said thermal means being arranged to release said switch member in response to predetermined current conditions, whereupon said switch member rotates about said pivot pin to an open circuit position independently of said toggle means.

6. A circuit breaker comprising a frame having a slot therein, a floating switch member having a pivot pin guided in said slot, toggle means including pivotally connected links one of which pivotally engages said pivot pin and another of which is pivotally supported on said frame, a torsion spring the respective ends of which engage said one toggle link and said switch member for biasing said switch member for rotation about said pivot pin, current responsive means for releasably restraining said switch member against rotation about said pivot pin, overcenter spring means for rotating said other toggle link about its pivot whereby said one toggle link moves said pivot pin along said slot to operate said switch member between open and closed circuit positions, said current-responsive means being arranged to release said switch member upon the occurrence of predetermined current conditions whereupon said torsion spring operates said switch member to an open circuit position.

7. A circuit breaker comprising a frame having a guide slot therein, a floating switch member having a pivot pin extending into said slot, a bell-crank lever pivoted on said frame, a link pivotally connected to one leg of said bell-crank lever and to said pivot pin, means including a torsion spring engaging said link and said switch member for biasing said switch member for rotation about said pivot pin, current-responsive means releasably restraining said switch member against rotation about said pin, means including an overcenter spring connected to another leg of said bell-crank lever for operating said bellcrank lever to move said pivot pin along said guide slot, whereby said switch member is operated between open and closed circuit positions, said current-responsive means releasing said switch member upon the occurrence of predetermined current conditions, whereupon said torsion spring rotates said switch member about said pivot pin to open circuit position.

8. A circuit breaker comprising a U-shaped frame having guide slots in the opposite legs thereof, a switch member nesting between said frame legs and having a pivot pin extending into said guide slots, said pivot pin being intermediate the ends of said switch member, toggle means for moving said pin along said slot including a first link pivoted on said frame and a second link connected to said first link and to said pivot pin, a pivoted operating lever, overcenter spring means connected between said operating lever and said first toggle link for operating said toggle to move said pivot pin along said slot in response to movement of said operating lever, thermal means normally restraining one end of said switch member against movement whereby the other end of said switch member is operated between open and closed circuit positions as said pivot pin moves along said slot, and biasing means for operating said switch member about said pivot pin to an open-circuit position independently of said operating lever when said one end of said switch member is released by said tli mal means. i

9. A circuit breaker comprising a floating switch member, means pivotally supportingvsaid switch member intermediate its ends, said pivot means being mounted for limited movement in a direction substantially at right angles to said switch member so as to provide for movement of said switch member between open and closed circuit positions, means biasing said switch member for rotation about said pivot means, current responsive latch means normally engaging one end of said switch member to secure said switch member against rotation about said pivot means, and overcenter spring operating means connected to said switch member for operating said switch I member with a snap action about said one end between its open and closed circuit positions, said current responsive latch means being arranged to release said one end of said switch member upon the occurrence of predetermined current conditions whereupon said iswitch member is rotated by said biasing means about said pivot means to an open circuit position. p

10. A circuit breaker comprising a current carrying switch member, pivot means supporting said switch I member intermediate its ends, a switch contact carried by one end of said switch member, means biasing said switch member for rotation about said pivot means to an open circult position, a bimetallic thermal current responsive element having a latchin portion normally engaging the other end of said switch membet to restrain said member against rotation about said pivot means to said open circuit position, a guide for said pivot means providing for limited movement of said switch member about said other end as a pivot between open and closed circuit positions, and overcenter spring operating means connected to said switch member for operating said switch member with a snap action between said open and closed circuit positions.

DAVID YS. 

